In many lighting applications, especially commercial lighting applications, an overhead lighting fixture is mounted relatively high above ground or floor level. The overhead lighting fixtures in a church are exemplary of this type of commercial lighting application. These fixtures may be fifteen to forty feet above the level of the floor. In addition, access immediately beneath the fixtures is limited due to the placement of rows of closely spaced pews.
Thus, replacement of the lights carried by such lighting fixtures is greatly complicated by the inability to position a conventional self-supporting or folding ladder on the floor below the fixture because of the pews. Moreover, many such self-supporting ladders do not have sufficient height to permit a technician to reach the lighting fixtures. A conventional extension ladder, although perhaps having sufficient reach to extend to the lighting fixture, may not be supported with sufficient stability to provide adequate safety. Accordingly, many burned-out lights must go unreplaced or worker safety unnecessarily compromised to replace the lights.
There are many other commercial settings where overhead lights are also difficult to access with conventional ladders. For example, in a factory setting, operating machinery or other work areas may be utilized beneath the lighting fixture making access with a conventional ladder impossible.
Attempts have been made to address the problem of servicing lighting fixtures which are suspended high above the ground or floor, or otherwise difficult to access using conventional equipment. For example, U.S. Pat. No. 4,430,694 to Koivumaki discloses a series of ceiling mounted fixtures mounted on horizontal tracks or rails so that the lighting fixtures can be laterally moved to another adjacent area for servicing. This approach requires an initial investment in rails and other hardware and presumes that an adjacent space provides better access. This approach is unusable or undesirable in many applications.
U.S. Pat. No. 1,473,713 to Thompson, and dating from 1919, discloses a lighting fixture having a fixed mounting base including a rotatable pulley, and wherein a length of rope is fed over the pulley and connected between a ground level location and the lowerable fixture. U.S. Pat. No. 1,454,855 to Larkins shows a similar fixture having a link chain in place of the rope.
Unfortunately, a rope or chain permanently connected to the lowerable fixture portion must be sufficiently long to extend down to adjacent ground level and permit lowering of the fixture portion. Accordingly, such a rope or chain is unsightly, interferes with efficient utilization of the space below the fixture, and creates an additional maintenance problem of ensuring the integrity of the ropes or chains on a periodic basis. For a large number of fixtures, or relatively high mounting of such fixtures, the ropes or chains are simply impractical.
While overhead lighting fixtures represent a particular and well known example requiring intermittent access for service or maintenance, other overhead electrical fixtures may also have a serviceable fixture portion requiring periodic or intermittent access for maintenance. For example, public address systems, scoreboards, and the like may include portions that are most conveniently and safely serviced adjacent ground level.